Tobeason graduated from Phillips Academy in Andover in 1976 and from Harvard University in Cambridge, Massachusetts in 1981. In 1988, he wrote the story for the Wiseguy episode "Smokey Mountain Requiem" which starred Jonathan Banks. He then worked as writer and producer on the short-lived television drama series Tribeca in 1993 for which he shared a Humanitas Prize nomination in the category 60 Minute Category in 1993 and a Writer's Guild of America Award nomination in the category Episodic Drama in 1994 with fellow writing and producing partner David J. Burke. The series featured Trek alumni Richard Kiley, Victoria Dillard, Caroline Kava, and Caroline Lagerfelt.

Following Tribeca, Tobeason was a consulting producer on the western/drama series The Adventures of Brisco County Jr. and a supervising producer and writer on the science fiction series SeaQuest DSV (1993-1994). The latter one featured Trek performers Stephanie Beacham, Marco Sanchez, Frank Welker, Richard Herd, and William Morgan Sheppard. Further projects as producer and writer include the action series The Marshal (1995), the science fiction series The Visitor (1997), the mystery series Strange World (1999), and the drama series Now and Again (1999). He also created the television movie DayBreak in 1998 as a pilot episode for a series which was not picked up.

Between 2002 and 2003, he worked as co-executive producer on the comic adaptation Birds of Prey which starred Trek guest stars Ian Abercrombie and Dina Meyer. In addition, he wrote the story for the episode "Sins of the Mother" in 2002 and was featured as an actor, a metahuman killed during an experiment, in the final episode "Devil's Eyes" for which he wrote the teleplay in 2003. Prior to his work on Birds of Prey, Tobeason worked as creator, executive producer and writer on the science fiction series Freedom between 2000 and 2001.

In 2007, Tobeason was executive producer on the reality television show Nashville and between 2007 and 2009 consulting producer/co-executive producer and writer on the drama series Saving Grace which starred Leon Rippy. The followig years he worked as co-executive producer and writer on the science fiction series V (2011), as consulting producer and writer on the crime series Damages (2012), and as co-executive producer and writer on the mystery series Cult (2013). The latter one starred Robert Knepper and Aisha Hinds and had Star Trek: Voyager scribe David Kemper as consulting producer.

More recently, Tobeason worked as executive producer on the fantasy series Believe (2014) for which he also wrote the first season episode "Second Chance". The series features recurring actor Nick E. Tarabay and was executive produced by J.J. Abrams and Bryan Burk.